The invention relates to a vacuum coating apparatus for applying thin coatings to substrates, having an entry chamber, at least one additional chamber for treating the substrates, and an exit chamber. A conveyor system disposed in an evacuable transport chamber carries the substrates through the chambers, the conveyor system being disposed around a common axis and holders which can turn about the latter. In at least two positions, namely an entry and exit position, the holders each perform a lifting movement with respect to the transport chamber wall, this lifting movement being such that in a first position the holder in a raised position closes the opening of the exit chamber in the wall of the transport chamber.
A disadvantage of known apparatus lies in its complex and expensive construction, and often also in the fact that they can be used only for a very specific substrate. Letting the substrates enter and exit through airlocks has resulted in often difficult sealing problems which have been solved by complex and expensive airlock designs.
U.S. Pat. No. 3,856,654 discloses a vacuum coating apparatus of the kind described above, in which the conveyor system has pot-like frames disposed about an axis of rotation, for the accommodation of substrates to be coated. In one treatment position, namely in the airlock entry and exit position, such a frame is itself part of the wall of the entry and exit chamber, and a movable valve plate is provided for shutting off one end face of the one part of the entry and exit chamber. In this known vacuum coating apparatus the passage through the airlocks of the goods to be coated is given a mechanically simple solution. However, the further movement of the substrates, especially to the position for coating, is complicated. The pot-like frame containing the substrate is brought by the further turning of the conveyor system to a transfer position from which the individual substrates are lifted from the pot-like frame by a lifting means acting on them from below and they are raised upward into the actual vapor coating chamber. The result is not only considerable mechanical complexity, but also complicated and time-consuming operation.
U.S. Pat. No. 3,915,717 discloses a vacuum coating apparatus for applying thin coatings to substrates, which has an entry chamber, additional chambers for the treatment and coating of substrates, and a conveyor system disposed in an evacuable main chamber for carrying the substrates through the chambers. Sealing systems for temporary sealing between the said chambers and the main chamber are provided, and the conveyor system has frames disposed about a common axis and rotatable about the latter for accommodating the substrates to be coated. In at least two treatment positions, namely an entry and exit position and a vapor depositing position, this frame itself forms part of the wall of a treatment chamber, namely the entry and exit chambers and a coating chamber. In at least one of these treatment positions a movable valve plate is provided for closing off one face end of the one portion of the frame that forms the treatment chamber.
The present invention is addressed to the problem of creating an apparatus of the type in question, in which the substrates will be disposed in special containers which can be passed together with the substrates through airlocks into the apparatus, and which will prevent contamination of the interior and of the conveying means due to the coating process. The apparatus is furthermore to be configured so that containers of different sizes can be used.
This problem is solved according to the invention in that a pot-like container to accommodate a substrate can be placed on each holder, and the outside diameter of each container is smaller than the inside diameter of the entry and exit openings, and the height of each container corresponds at least to the total lift height of the holders, and the holder lifts up the container at the treatment position to such a level that the upper margin of the container is applied sealingly to the margin of the opening to the treatment chamber or to a collar or mask inserted into the opening and narrowing the latter, the diameter of the opening determined by the opening in the wall or by the collar or by the mask being smaller than the outside diameter of the upper margin of the container.